Which of the following is quartan in periodicity ?

Options

A. P. malariae
B. P.vivax
C. P. ovale
D. p.falciparum

Answer

To solve the question "Which of the following is quartan in periodicity?", we need to analyze the options given, which are different species of the Plasmodium protozoan that causes malaria.

### Step-by-Step Solution:

1. **Understand Malaria**: Malaria is a disease caused by protozoan parasites of the genus Plasmodium. There are several species of Plasmodium that cause malaria, and they can be classified based on the periodicity of fever they induce.

2. **Identify Types of Malaria**: There are two major types of malaria based on fever periodicity:
- **Tertian Malaria**: Characterized by fever that occurs every second day.
- **Quartan Malaria**: Characterized by fever that occurs every third day.

3. **List the Plasmodium Species**: The options provided are:
- Plasmodium malariae
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium falciparum

4. **Determine the Fever Patterns**:
- **Plasmodium malariae**: Causes quartan malaria (fever every third day).
- **Plasmodium vivax**: Causes benign tertian malaria (fever every second day).
- **Plasmodium ovale**: Also causes benign tertian malaria (fever every second day).
- **Plasmodium falciparum**: Causes malignant tertian malaria (fever every second day).

5. **Conclusion**: From the analysis, we can conclude that the only species that causes quartan malaria is **Plasmodium malariae**.

### Final Answer:
The correct answer is **Plasmodium malariae**.